//题目链接：https://leetcode.cn/problems/sort-colors/
class Solution 
{
public:
    void sortColors(vector<int>& nums) 
    {
        int n=nums.size();
        int i=0,left=-1,right=n;
        while(i<right)
        {
            if(nums[i]==0)
                swap(nums[++left],nums[i++]);
            else if(nums[i]==1)
                i++;
            else 
                swap(nums[--right],nums[i]);
        } 
    }
};